A new Nevada Senate poll by Fox News has Republican Sharron Angle up by 3 percentage points over incumbent Sen. Harry Reid. But a political science professor in the state questions its validity.

According to Fox News, Angle is up 49 percent to 46 percent in a poll conducted Saturday of 1,000 likely Nevada voters. "As voters make up their mind with four weeks to go until Election Day, Angle seems to have the edge," Fox News said.

The margin of error on the survey was plus or minus 3 percentage points, Fox News said.

But in discussing the poll, College of Southern Nevada professor Mark Peplowski questioned the sample. It appeared weighted, he said, with 48 percent of the respondents identifying themselves as conservatives, 26 percent as moderates and 25 percent as liberal.

"It looks like it is a little bit heavier on the right side of the spectrum for Nevada's constituency," Peplowski said.

Self-identified Republicans also outnumbered Democrats in the poll, while the latest figures from the Nevada Secretary of State show Democrats with a 58,000 lead in registration.

Other recent polls have the race deadlocked or with Reid with a slight lead. One poll, conducted Sept. 21-23 by a Republican firm for the Nevada Retail Association had Reid ahead 45-40.

"I would look askance on this poll," Peplowski said of the Fox News survey. "It doesn't seem to be following the trend that we've been seeing for the last 30 days of Reid gradually crawling back up and taking the lead, and all of a sudden he is dropping back five or six points? I don't think anything would have motivated that happening. I think the sampling calls into question the validity of these results."

Peplowski also noted the poll may be dated. It was conducted on Saturday, before the latest twist in the race, the disclosure that Angle tried to persuade Scott Ashjian, the Tea Party of Nevada candidate, to drop out. Ashhjian secretly taped the conversation, which caught Angle offering him her influence with Republican senators if she is elected.